Processes of getting a car btw im a teen?

I want to get a car by this summer before I become a senior but I need help. I know I need to get my license but I need a car for that also a job. I want to know what you do to get a car like about how much money would I need? I want to get a mercedes,infiniti, bmw, or lexus but it has to be used since its cheaper. What would I need to do because I have no idea.